1. Field of the Invention
This invention is related to an X-ray generator and X-ray generation. For example, the X-ray generator may be used for nondestructive testing for inspecting am aluminum castings (an integrated circuit), and so on for X-ray analysis, with an industrial X-ray apparatus for obtaining an X-ray picture of a cell, and so on.
2. Description of the Related Art
An X-ray generator has a tube body 01 the inside of which is kept in a vacuum state, as shown in FIG. 9. The body 01 has an electron source 02 and a target member 03 therein. The target member 03 has a base member 05, made of Aluminum, for example, on which a metal target 04 of Tungsten, for example, is evaporated. The base member 05 is attached to the body 01.
The body 01 has an electrode 06 for pulling an electron beam out of the electron source 02 and an electron lens 07. The electrode pulls out electrons as an electron beam from the electron source 02 and the lens 07 converges the beam. The converged electron beam is irradiated onto the metal target 04 and then the metal target 04 generates X-rays.
When it is necessary to make the focal point smaller to inspect an microscopic object, a small X-ray focal point on the large metal target 04 is created by converging an electron beam at a much smaller point with the electron lens 07. In the above structure, it is impossible to make an X-ray focal point smaller than a certain size because electrons with negative charge in the X-ray beam repel one another. It is also necessary to cool the electron lens 07 which generates heat in use. Therefore, the X-ray generator becomes large because of the need for a cooling system for the electron lens 07.
It is therefore an object of this invention to provide a low-cost and small X-ray generator which has a small X-ray focal point.